State of the Art in Inductive Charging for Electronic
Appliances and its Future in Transportation
Neha Chawla
Sabri Tosunoglu
Department of Mechanical and Materials Engineering
Florida International University
Miami, Florida, USA
Department of Mechanical and Materials Engineering
Florida International University
Miami, Florida, USA
786-419-0915
305-348-1091
nchaw002@fiu.edu
tosun@fiu.edu
allowed in the output of the system. Low maintenance required
thus decreasing the cost of the system comparatively. Inductive
charging makes charging mobile devices and electric vehicles
more convenient; rather than having to connect a power cable, the
unit can be placed on or close to a charge plate.
ABSTRACT
Inductive charging is a method of moving power wirelessly. A
power generating source system is placed near a power storing or
power transferring system. An electromagnetic field is generated
between the two objects and power is moved from one system to
the other. Inductive charging is a way of moving power from a
main system to a subsystem such as moving the power from the
power grid to a local transformer. It is applied to a wide variety of
systems from small hand-held devices to robotic platforms and
electric vehicles. In this study, the working principle, advantages,
disadvantages and limitations of inductive charging mats/pads
used for electronic devices are discussed. The new advancements
in inductive charging for transportation are also reviewed in this
study.
1.2 Limitations:
The main disadvantages of inductive charging are heat and power
consumption. It takes more power to inductively charge an item
than charge it through normal means. This is due to the power lost
to the electric field used to connect the coils. The process has the
potential to generate immense heat indicating the amount of
electricity being lost in the process of charging. Inductive
charging also requires drive electronics and coils, increasing the
complexity and cost of manufacturing. Using high frequency
switches in electronic converters may cause interference in nearby
equipment. The system may not work or the losses may increase if
there is any metallic object in the middle of the magnetic
connection. Magnetic radiation is harmful for the user’s health. At
the frequencies of interest in IPT systems a maximum of 2.6 uT is
allowed to be exposed to the body. This being an averaged
exposure limit and it has been described by Australian Radiation
Protection and Nuclear Safety Agency (ARPANSA). Newer
approaches reduce transfer losses through the use of ultra-thin
coils, higher frequencies, and optimized drive electronics resulting
in more efficient and compact chargers and receivers, facilitating
their integration into mobile devices or batteries with minimal
changes required.
1. INTRODUCTION
Inductive charging works on the basic principle in which two
power systems are placed very close to one another. They need
not to be exposed or connected to each other. Each of these power
systems contains an electrical coil that stores electricity for the
device’s use. The coils’ proximity to each other results in the
generation of a low power electrical field that connects them. This
field allows the transfer of electricity between the two systems.
The two systems share electricity until they both have exactly the
same amount of power. In inductive charging, one of the devices,
i.e., the sender, is constantly powered so that it can send power to
the receiver continuously until the receiver is fully charged.
1.1 Advantages:
Table 1. Summary of Advantages and Disadvantages of
Inductive Charging
Induction charging has several advantages over standard power
transfer. One major benefit is that it is wireless. There is no
limitation on the number of devices that may be charged at once.
Hence, a single inductive charging mat can charge several devices
at the same time. Inductive charging carries a far lower risk of
electrical shock when compared with conductive charging,
because there are no exposed conductors.
•
•
•
•
The ability to fully enclose the charging connection also makes
the approach attractive where water impermeability is required;
for instance, inductive charging is used for implanted medical
devices that require periodic or even constant external power, and
for electric hygiene devices, such as toothbrushes and shavers,
that are frequently used near or even in water. Due to
encapsulation it can be used in harsh environments. High power is
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•
•
•
•
1
Advantages
Wireless
A number of devices can be
charged at a time
Electrically safe
Can be used in harsh
environments due to
encapsulation
High power in output
Waterproof
Low maintenance
Charging is convenient
•
•
•
•
•
•
Limitations
More power
consumption
Low efficiency
Heat generation is more
than traditional charging
Complex circuitry
High cost of
manufacturing
Harmful magnetic
radiations emitted
Boca Raton, Florida, May 10-11, 2012
inductive coupling to an electrical device, which then can use that
energy to charge batteries.
2. HISTORY
In 1901, Nikola Tesla used the principle of electrodynamic
induction to transfer electromagnetic energy without the need of
wires to construct the Wardenclyffe tower (Figure 1) to transmit
power between America and Europe but was destroyed by US
government in 1917.
There is a small gap between the two coils employed in each of
the sender and receiver of the energy within the respective devices
due to which inductive charging is considered a short-distance
wireless energy transfer, despite the fact that there are typically
more wires used with inductive charging than direct-contact
charging, because it frees the user from having to deal with wires
between the two devices.
Induction chargers typically use an induction coil to create an
alternating electromagnetic field from within a charging base
station, and a second induction coil in the portable device takes
power from the electromagnetic field and converts it back into
electrical current to charge the battery. The two induction coils in
proximity combine to form an electrical transformer.
Wireless charging is an emerging trend for mobile and portable
devices with various products appearing in the market by
providing significant user convenience. Magnetic resonance based
charging is a technique that provides support for charging
multiple receivers with the same transmitter. Wireless charging
has been popular since 2009 with products like Palm Pre., Dell
Latitude, PowerMat and many other similar products.
The technologies for wireless charging can be either magnetic
induction or radio frequency or optical or conduction. Magnetic
induction converts electrical energy to magnetic energy. It allows
transmission over an air gap and is typically short to midrange.
For microwave or radio frequency, the parabolic dish focuses
radio waves which are typically long range waves towards
intended target. They can also include low power receivers for
energy harvesting. For optical or infrared, the laser light is
focused on photovoltaic cells that convert light energy to power.
In conduction, the power transfer occurs due to metallic contact
between transmitter and receiver. Compared to inductive coupling
and RF radiation, wireless power transfer via strong coupled
resonance is more suitable for wireless power transfer in a range
from a few centimeters to a few meters for mobile consumer
devices. Many researches have been conducted to investigate the
principle and design of wireless power transfer via strong coupled
resonance. A wireless charger prototype based on strong coupled
magnetic resonance was presented and emphasis was put on
design considerations and experiments for real wireless power
transfer applications based on this technology.
Figure 1. Wardenclyffe Tower
Andre Marie Ampere discovered 200 years ago that a magnetic
field is created around the wire if electricity is transmitted down a
wire. Then Michael Faraday developed the fundamental law of
induction, a process that enables the transfer f power from one
wire to another using magnetic field. Later the Maxwell equation
was established, which is the basis of several everyday devices
including electrical motors and generators. The basic technique
used by Tesla earlier is now used in any situation where batteries
are being charged without physical contacts. It is used in
recharging electric toothbrushes or wet/dry electric shavers.
Induction cooktops that transfer energy directly to a pot’s metal
bottom but remains cool to touch also uses the same principle.
In 2007, MIT researchers proposed the wireless power
transmission based on strong coupled magnetic resonance and
successfully lightened a 60 W bulb over 2 meters with a transfer
efficiency of 30%. In 2008, Intel demonstrated an experiment
setup to lighten a 60 W bulb over 1 meter with the transfer
efficiency of 70 %.
Magnetic induction has two categories namely magnetic induction
coupling and magnetic resonance coupling. In inductive coupling,
the source drives a primary coil creating a sinusoidally varying
magnetic field which induces a voltage across terminals of
secondary coil, thus transferring power to load. This type of
mechanism is used in transformer where the magnetic field is
confined to high permeability core. Magnetic resonance coupling
is more advantageous since it has an extended range, alignment
insensitivity and potential to support multiple receivers. The gain
is over a very small range implying that very accurate tuning is
required for magnetic resonance coupling.
3. INDUCTION CHARGING MATS/ PADS
Induction powers the charging mats that wirelessly transfer energy
to the devices and allows them to be recharged by simply placing
them on the top of the mat. Inside the mat there is an inductive
coil through which the electricity runs and the power is transferred
to a second coil attached to the device. Inductive charging uses an
electromagnetic field to transfer energy between two objects. This
is usually done with a charging station. Energy is sent through
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5. MULTIPLE RECEIVER CHARGING
Figure 2. Magnetic Resonance Coupling Circuit Model [8]
Figure 2 shows the circuit model for magnetic resonance. The
transmitter (source) is the charger and the receiver (load) is the
device to be charged. The source and load are inductively coupled
to the resonant circuits to remove the effect of loading (parallel
impedances), which results in a high Q of the circuit.
4. SINGLE RECEIVER CHARGING
Figure 4. Multiple Receiver Charging [8]
Figure 4 shows the multiple receiver charging. A split resonant
peak is caused by the coupling to the first receiver when a second
receiver comes close to the transmitter. The receiver detects the
loss in power transfer due to multiple receiver coupling which is
reported to the transmitter by receiver. After the information of
the loss is received, the transmitter estimates the reasoning behind
power transfer loss. It first searches for alternate receivers in
vicinity using its communications interface. It then sweeps from
frequency fc to fd with stepsize s = (fd – fc)/N where N is the
number of steps in the sweep. If other receivers are detected then
each receiver receives the sweep and notes the frequency sweep at
which maximum power was transferred. Maximum power transfer
occurs at different frequencies for each receiver. Results of the
sweep are communicated back to the transmitter via
communications interface.
Figure 3. Single Receiver Charging [8]
The single receiver charging system consists of a transmitter and
receiver designed to operate at a frequency for resonance power
transfer as shown in Figure 3. The frequencies of transmitter (f1)
and receiver (f2) may deviate due to process, voltage and
temperature variations inside the components of a device or due to
the presence of metallic elements in or near the device. The
frequency tuning is done by changing the capacitance or
inductance values via a shared communication interface between
transmitter and receiver by frequency sweep which can be
performed by finely adjusting the resonant circuit at transmitter
over the desired range of operation. Assuming the mobile to be
stationary, the maximum power transfer from transmitter to
receiver occurs at frequency f2; i.e., the operating frequency of
receiver. Receiver keeps the record of the power level received for
each of the sweep steps. The sweep step is then reported to the
transmitter by the receiver where maximum power transfer occurs
back to transmitter via communications interface. The transmitter
then tunes its circuit to frequency f2 and transmits at f2 for
maximum power transfer efficiency.
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The transmitter contains multiple resonance structure to
communicate with multiple receivers. The number of
simultaneous receivers supported by this method is dependent on
the number of resonance structures available at the transmitter.
The transmitters can time-multiplex between the multiple
receivers and retune to operating frequency of each receiver
which allows supporting charging a greater number of receivers
than the number of resonance structures available at the
transmitter. The time multiplexing is dependent on the current
charging status for each receiver and the transmitter and allocates
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more time to the receiver which is less charged. Time
multiplexing helps reducing coupling between the receivers and is
used when the coupling is very strong and the resonant peaks are
outside the tuning range of the transmitter.
charged, saving on unnecessary power use or overcharging your
batteries. Duracell have implemented touch sensitive safety
procedures that power off the device when it comes into contact
with your fingers or inappropriate metallic objects.
6. PRODUCTS AVAILABLE IN MARKET
6.3 Energizer Inductive Charger
Various products available in the market for inductive charging
are discussed below.
6.1 PowerMat 3X
Figure 7. Energizer Inductive Charger [10]
Energizer Inductive Charger as shown in Figure 7 is based on Qi
Technology and aims to be the next-generation charging solution
for many devices. The Energizer Inductive Charger conveniently
charges up to three of your devices at one time. Two inductive Qi
charging zones are located on the top surface of the pad for
simple, easy charging. For both Qi and non-Qi devices, the USB
port on the back is ideal for charging additional phones, headsets,
mp3 players, cameras, GPS devices, and any other device up to 5
watts. The charging pad offers two stations to charge devices.
Additionally, the two LEDs above each station will illuminate in a
neon blue color to indicate that it actively charges the device.
Even though the charging pad slopes down at an angle, devices do
not slide or move around. On the back, there is the proprietary
charging port and a standard USB port, which allows the user to
charge other devices.
Figure 5. PowerMat 3X [9]
PowerMat 3X as shown in Figure 5 is a sleek, slim three position
wireless charging mat for home and office. A magnetic attraction
between every receiver and each access point on every Mat
assures that alignment is precise and the most efficient charging
occurs. Communication between the Mat and the Receiver allows
the mat to deliver an exact amount of power for the proper length
of time so that the transfer of power is safe and efficient and no
energy is wasted. When the device reaches full charge, power is
shut off to that device, which avoids overcharging of the device's
battery as well as saves energy. Once full power is achieved and
the Auto Shut Off has occurred to save energy, the system will
monitor the status of the battery in the device. If the battery is
used, the system will again initiate charging and return the battery
to a full charge.
6.4 WildCharge Pad
6.2 Duracell MyGrid
Figure 6. Duracell MyGrid [11]
Figure 8. WildCharge Pad [12]
The Duracell MyGrid Charging Pad as shown in Figure 6 is a flat
square with a single raised edge. It measures 8 by 6.5 by 0.75
inches at its largest point and fits easily on a desk or bedside table.
It consists primarily of 12 magnetic strips, which carry the actual
charge to the devices. With a maximum power output of
15VDC/1A, it's a very efficient device, charging all four gadgets
in more or less the same amount of time as by using their bespoke
power adapters, all the while saving around 15% on energy
consumption. The myGrid switches off once each device is fully
Pure Energy Solution’s WildCharge Pad as shown in Figure 8
wireless phone charger offers comparable features and output
capabilities. The WildCharge Pad provides 15 watts of output
power, enough to charge multiple devices simultaneously. It
works through the traditional contact-point transference principle
where two conductive materials transfer electricity to charge the
battery.
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Table 2. Comparison of the Various Induction Charging Products Available in the Market
Comparison Points
PowerMat 3X
Duracell myGrid
Energizer
Inductive Charger
Wild Charge Pad
Excellent
Good
Fair
Good
Excellent
Fair
Good
Fair
Excellent
Fair
Good
Fair
Excellent
Fair
Good
Good
Compatible with
Iphone 3G/3GS and
Blackberry curve
Compatible with
Iphone 3G/3GS,
Ipod Touch,
Blackberry Curve,
Blackberry Bold,
Blackberry Pearl,
Nintendo DS/DSi,
Overall Rating
Device compatibility: This section
rates the wireless chargers on their
compatibility with select mobile
devices
Specifications: This section rates
each wireless charger on its output
capacities including output watts
and device features
Durability/Ability to endure
damage
Help and support provided by the
manufacturer
Features
Device compatibility
Maximum no of devices the
wireless charger can power at
once
Power output (Watts): No of watts
that the wireless charger produces
Internal battery: It allows the
devices to charge mobile gadgets
without the pad being plugged
into the wall
Full charge shutoff: This feature
stops sending power to devices
once they reach full charge
Compatible with
iphone4, 3G/3GS,
Ipod Touch,
Blackberry Curve,
Blackberry tour,
Blackberry Bold,
Blackberry Pearl,
HTC EVO 4G,
Motorola DROID
X, Nintendo
DS/DSi,
Compatible with
iphone4, 3G/3GS,
Ipod Touch,
Blackberry Curve,
Blackberry Tour,
Blackberry Bold,
Blackberry Pearl,
Motorola DROID X
3
4
3
4
18
15
15
15
Has internal battery
Does not have
internal battery
Does not have
internal battery
Does not have
internal battery
This feature is
available
This feature is not
available
This feature is
available
This feature is not
available
disadvantage of using cable and connector type is the risk of
electrocution especially in wet and hostile environments since it
delivers 2- 3 times more power than standard plugs at home. Long
wires also pose a tripping hazard and are also aesthetically poor.
In harsh climate locations that have snow and ice, the plug-in
charge point may become frozen onto the vehicle. Thus in order to
eliminate the above disadvantages, the inductive charging has
been developed which can charge the batteries wirelessly. Road
electrification as shown in Figure 9 can be developed so that the
power is transferred to the vehicle as it moves along the electrified
section of the roadway. It would eliminate the problem of range
with EVs as the required power by the vehicle travelling on
freeways can be supplied by the grid directly through the roadway
but the infrastructure cost is high.
7. INDUCTIVE CHARGING IN
TRANSPORTATION
Transportation sector is the largest consumer of fossil fuel
worldwide and thus important factor in reducing fossil fuel
demand. Pollutant emissions and oil consumption are caused by
transportation sector. Currently the transformation in automobiles
from internal combustion engines (ICE) vehicles to hybrid fuel
cells vehicles (FCV). The limited availability of fossil fuel and to
reduce the emissions in transportation sector, the development of
electric vehicles worldwide over the past decade has been
initiated. The price of EV is nearly twice than that of ICE
vehicles which is largely due to the limitation of battery
technology. The charging time of EV is very long when compared
to ICE car.
Currently, plugin connections are used in EVs for charging where
the user inserts the plug into the receptacle of the car to charge the
batteries. It has the following disadvantages.
The major
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compensates the reactive part of total impedance by increasing the
power transfer efficiency. Battery charger controls the charging
process and changing voltage to the levels accepted by each type
of battery. The magnetic linkage and resonant circuit are the most
important parts of the IPT system.
Charging of lithium battery for portable electronic products and
concept of common charging applies contactless power
transmission technique. Charging platform comprises of several
pot type cores with array structure, allowing circuit to be charged
within a permitted region of displacement on charging platform.
Poor power transmission efficiency occurs since a larger air gap
exists in contactless structure compared to other contact
structures.
Figure 9. Electrified Road (Efficiency can be kept high if the
magnetic field is only turned on at the instant the vehicle is
travelling over it [5])
First, high frequency alternating currents are produced by the
power supply in transmitter pad that inductively transfers power
to receiver coil. The receiver electronics converts this high
frequency power that was received via induction to DC which is
suitable for charging. These systems are mostly loosely coupled;
hence resonance and high frequency operation is required.
Figure 12. The Framework of Contactless Inductive Charging
Platform [5]
Adoption of an inductive power transfer system (IPT) as shown in
Figure 10, to charge the batteries on board the electrical vehicle
has been proposed by A. Neves et Al. It is known as wireless
electrical charger for the inexistence of physical contact between
the source and the load.
Hung-Yu Shen et Al. aimed at providing convenient and uniform
charging method for portable electronic products using contactless
inductive charging. Figure 12 shows the framework of contactless
inductive charging platform. Upon designing contactless inductive
charging system, the analysis of magnetic allocation for inductive
structure is the first consideration, relying on the result of analysis
to obtain appropriate inductive structure and to consider the
impact of current direction of array core on the allocation of
magnetic fields. Next, closed-loop control structure is applied,
enabling the system to work in the domain of high efficiency. The
structure of contactless inductive charging platform proposed in
this research is shown in Figure 12. It shows that the converter
transforms AC into DC and then the inverter again transforms the
DC into AC for driving inductive core of the primary. In the
secondary, the inductive core picks up power from primary and
the power is then rectified in order to charge the lithium battery.
The charging scheme utilized in the research was constant current
and constant voltage. Their research analyzed the magnetic field
allocation of different core and considered the impact of induced
magnetic field on other electronic equipment.
Figure 10. Inductive Charging System [5]
The charging platform was then designed by several pot type
cores with magnetic enclosure due to the analysis results. The
influence of current direction of the coil on allocation of magnetic
field was investigated to choose appropriate induced structure and
current direction of the coil. Microprocessor control circuit is
utilized to adjust input power when the secondary is removed
from the charging platform and reduces energy depletion. The
coupling effect of each part of the charging platform was shown
to provide the best position to place the secondary. Additionally,
the induced structure was implemented leading to plane circuit.
Result of experiment showed that the contactless inductive
charging platform was able to charge a battery with charging
current of 200mA under the condition of a gap 2.5mm between
the secondary and the charging platform. The highest transfer
efficiency was found to be 55% between primary and secondary
was able to work normally within a large enough displacement.
Figure 11. Main Blocks of an IPT Vehicle Charging System:
(1) Power Source, (2) Magnetic Link, (3) Resonant Circuit,
and (4) Battery Charger [5]
Basic circuit of an IPT vehicle as shown in Figure 11 constitutes
of 4 major blocks namely a power source, a magnetic link, a
resonant circuit and a battery charger. Power source is for
connection between magnetic link and power grid and is
composed by and rectifier followed by an inverter. The current
amplitude and frequency can be controlled by allowing power
flow of the system. The magnetic linkage transfers the power
between battery charger and power source and is composed of 2
coils that have either an iron core or no core. The resonant circuit
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Qualcomm Halo WEVC has developed an inductive charger that
consists of two parts: a charging plate that attaches to the bottom
of the vehicle and a charging mat that can be placed on or below
the ground. Inductive charging uses magnetism to transfer power
up to 3.5 kilowatts at greater than 90 percent efficiency. Their trial
will be in London and will span over a period of 2 years and
involve about 50 cars.
Part of energy was lost in leakage inductance of induced structure.
Transfer efficiency can be improved by overcoming the above
weakness and by other type of induced structure and magnetic
material added to increase the coupling coefficient.
8. STATE OF THE ART OF INDUCTIVE
CHARGING FOR TRANSPORTATION
Magne Charge inductive charging was employed by several types
of electric vehicles around 1998 but was discontinued after
California Air Resources Board selected SAE J1772 in 2001 or
Avcon conductive charging interface for electric vehicles in June
2001. In 2009, Evatran, began development of Plugless power for
proximity charging system for electric vehicles. With the
participation of the local municipality and several businesses,
field trials were begun in March, 2010, on the system scheduled to
be available in fourth quarter 2010.
9. CONCLUSION
Wireless energy transmission technology has been developed in
which electrical energy is transmitted from power source to an
electrical device without using wires. The limited fossil fuel
availability throughout the world has allowed the electric vehicles
to develop over the past decade. The technology has improved
sustainability but still consists of various drawbacks which need
to be researched upon in order to commercialize it.
Researchers at Korea Advanced Institute of Science and
Technology have developed an electric transport system where
vehicles get their power needs from cables underneath the surface
of the road surface via non- contact magnetic charging where
power source is placed underneath the road surface and power is
wirelessly picked on the vehicle by itself. It will improve overall
efficiency by minimizing air resistance and thus reduces energy
consumption.
10. REFERENCES
[1]
Michael G. Egan, Dara L. O’Sullivan, John G. Hayes, Michael J.
Willers, and Christopher P. Henze, “Power-Factor-Corrected
Single-Stage Inductive Charger for Electric Vehicle Batteries,”
IEEE Transactions on Industrial Electronics, vol. 54, No. 2, pp.
1217-1226, April 2007.
[2] Yun You, Boon Hee Soong, Selva Ramachandran and Wei Liu,
“Palm Size Charging Platform with Uniform Wireless Power
Transfer,” 11th Int. Conf. Control, Automation, Robotics and
Vision, Singapore, pp. 85-89, December 7-10, 2010.
[3] Hung-Yu Shen, Jia-You Lee, Tsunug-Wen Chang, “Study of
Contactless Inductive Charging Platform with Core Array
Structure for Portable Products,” CECNet, International
Conference, pp. 756-759, April 2011.
[4] A. Neves, D. M. Souza, A. Roque, J. M. Terras, “Analysis of an
inductive charging system for a commercial electric vehicle,”
Proceedings of the 2011 – 14th European Conference on Power
Electronics and Applications, pp. 1-10, Lisbon, Portugal, Aug.
30 – Sep. 1, 2011.
[5] Hunter Hanzhuo Wu, Aaron Gilchrist, Ky Sealy, Paul Israelsen,
Jeff Muhs, “A review on inductive charging for electric
vehicles,” IEEE International Electric Machines and Drives
Conf., pp. 143-147, May 2011.
[6] Yanping Yao, Hongyan Zhang, Zheng Geng, “Wireless charger
prototype based on strong coupled magnetic resonance”,
International Conference on Electrical Engineering and
Information Technology, pp. 2252-2254, August 2011.
[7] Huiqing Zhai, Helen K. Pan and Mingyu Lu, “A practical
wireless charging system based on Ultra-Wideband retroreflective beamforming,” IEEE Antennas and Propogation
Society International Symposium (APSURSI), Arlington, Texas,
July 1-17, 2010.
[8] Sridhar Rajagopal and Farooq Khan, “Multiple receiver support
for magnetic resonance based wireless charging,” June 2011.
[9] Review of PowerMat 3X, 2012.
[10] Energizer official site for Energizer inductive charger, 2012.
[11] Duracell MyGrid official site, 2012.
[12] Review of Wild Charge Pad, 2012.
The major advantage of the inductive approach for vehicle
charging is that there is no possibility of electric shock as there are
no exposed conductors, although interlocks, special connectors
and RCDs (ground fault detectors) can make conductive coupling
nearly as safe. An inductive charging proponent from Toyota in
1998 contented that overall cost differences were minimal, while a
conductive charging proponent from Ford contended that
conductive charging was more cost efficient.
From 2010 onwards, car makers are signaling their interest in
wireless charging as another piece of the digital cockpit. In May
2010, a group by the Consumer Electronics Association set a
baseline for interoperability for chargers.
In November 2011, the Mayor of London, Boris Johnson, and
Qualcomm announced a trial of 13 wireless charging points and
50 EVs in the Shoreditch area of London's Tech City, due to be
rolled out in early 2012.
Halo Wireless Electric Vehicle Charging (WEVC) technology
seeks to solve this problem with wireless inductive charging for
electric vehicles. Qualcomm Halo WEVC has basically taken
inductive charging--which you probably already see in devices
such as your electric toothbrush--to the next level, by making it
possible to send kilowatts "over an air gap of hundreds of
millimeters while still maintaining high-energy transfer
electricity."
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